X-ray apparatus



H. c. BERTRAM ZJQJM X-RAY APPARATUS Filed March 11, 1938 2 Sheets-Sheet1 W, Wm H. c. BERTRAM 9 9 X-RAY APPARATUS Filed March 11, 1938 2Sheets-Sheet 2 i atented Dec. 19, 1939 UNITED STATES PATENT OFFlCE X-RAYAPPARATUS Application March 11, 1938, Serial No. 195,409 In GermanyMarch 17, 1937 Claims.

My invention relates to X-ray apparatus, and particularly to asupporting device for an X-ray tube for investigating stresses inmaterials.

For this purpose, it is common practice to make 5 three radiographs fromthe surface of the body to be examined, which may be a work-piece or amachine part, by causing the X-rays reflected and dissipated from thesurface to act upon a photographic layer. In making these radiographs, anarrow X-ray beam is caused to impinge in three different directionsupon the same point of the surface of the body. For one of theseradiographs, the X-ray beam extends normal to the surface; for thesecond radiograph it makes an angle of 45 with the surface of the bodyand lies in a plane which is normal to the surface of the body andpasses through the direction of the stress to be measured; and for thethird exposure it forms an angle of 45 with the surface of the body andlies in a plane which is normal to the first plane and to the surface ofthe body.

With existing apparatus it is very difncult to accurately adjust theX-ray tube together with the diaphragm and exposure device into each ofthese three directions of exposure, and the operation of such apparatusis very time-consuming.

The object of my invention is to overcome the above difliculties and toprovide an X-ray apparatus with which the X-ray beam can be quicklyplaced in any of the above positions.

Another object of the invention is to provide an apparatus in which theX-ray beam is accurately located in these positions.

Still further objects and advantages attaching to my apparatus and toits use and operation will be apparent to those skilled in the art fromthe following particular description.

In accordance with the invention, I so support 40 the portion of theapparatus carrying the X-ray tube together with the aperture-diaphragmwhich serves for the obtainment of the narrow ray beam and in some casesthe film-holder. that it can be 45 rotated about the axis of a conicalsurface of which the three directions of exposure are generatices, andthe directrix is a circle. During the three exposures this axis forms anangle of about with the X-ray beam defined by the aperture- 50diaphragm, and intersects this beam on the side of the apertureddiaphragm remote from the X-ray tube so that it is possible to bring thevertex of the conical surface into the surface of the material whosestresses are to be investigated.

55 I also provide means for accurately locating and holding theapparatus in each of the three positions.

In order that the invention may be clearly understood and readilycarried into effect, I shall describe the same in more detail withreference 5 to the accompanying drawings, in which:

Figure 1 is a perspective diagram illustrating the principle of theinvention.

Figure 2 is a sectionized side view of one form of construction of adevice according to the 10 invention.

Figure 3 is a sectionized view along line XX of Fig. 2, and

Figure 4 is a perspective view of the apparatus mounted upon a stand. 15

In Fig. 1, the reference numeral 30 indicates a plate of a material inwhich stresses indicated by lines S and T are to be determined at apoint 0 on the surface thereof. Perpendicular to the surface of plate 30and passing through lines S 20 and T respectively, are two planes D andE intersecting in a line A0 which is also perpendicular to the surfaceof the plate 3!]. One of the three exposures, which as mentioned aboveare usually made for determining the stress in the plate 30, 25 is takenalong line A0 in the direction indicated by the arrow. Lying withinplane E and making an angle BOS of 45 with the line OS is a line BOwhich represents the direction in which a second exposure is taken.Lying within plane D and 30 making an angle COT of 45 with the line OTis a line G0, which represents the direction in which the third exposureis taken.

Assuming that A0, B0 and C0 are of equal length, a circle F drawnthrough the points A, B 35 and C will have its center at a point P. Aline PO can then be considered as the axis of a cone and forms an angleof 30 20' with each of the lines A0, B0 and CO. Thus, lines A0, B0 andC0 are generatrices of a conical surface of revolution whose axis ofrotation is the line PO and whose directrix is the circle F.

According to the invention, the X-ray tube, together with the apertureddiaphragm, is adapted to rotate about an axis of rotation whichcoincides with the cone-axis OP. Thus it is only necessary to rotate thetube about the axis of rotation to bring the X-ray beam into either ofthe directions A0, C0 and B0.

Preferably, I provide means for quickly locating the X-ray beam ateither of the positions indicated by lines A0, C0 and B0, for instanceby a set of adjusting marks, or a braking or locking device by which thedesired angular displacements about the axis of rotation of the meridianplane through the ray beam are rendered readable or perceptible. As boththe angles APB and APC have a value of about 98 and the normaladjustment, 1. e., when the X-ray beam lies in the direction A0, can ofcourse be readily found, by rotating the X-ray tube around the axis OPby 98 to the left and to the right of the normal position the raydirections B0 and C0 are determined. The adjusting marks, or the like,may be so formed that two of the meridian planes in which the X-ray beamis located for the adjustments determined by them form with each otheran angle of about 200, preferably of 196, and the third one, i. e.,corresponding to line A0, divides this angle into two equal parts.

One construction of my apparatus according to the invention isillustrated in Fig. 2 in which reference numeral 3! designates an X-raytube having an envelope l provided with an X-ray window 23, and an anode2 provided with a target 32 upon which a focal spot 3 is formed duringoperation.

The X-ray tube is supported by a suitable clamping ring A provided witha trunnion 5 rotatably mounted on an arm 6 of a supporting member Ascrew 7 serves to hold trunnion 5 in the desired position. Member 33 hasa flange portion ii, and an annular portion 8 carrying a diaphragm 9 ofY-ray absorbent material, such as copper or lead, and provided with anaperture 10. Aperture it serves to form the X-rays leaving tube 3ithrough window 23 into a narrow beam, and a film holder .2? carried byportion 8 serves to hold the films for receiving the X-rays reflectedfrom the body 30.

Secured to portion ll of member 33 is a pivot H which is rotatablymounted in a cylindrical member 92. The axis 25 of the pivot (whichcorresponds to the line P0 in Fig. 1) forms an angle of 30 20 with theline 25 which is the axis of the X-ray beam leaving aperture it]. Withthe apparatus in the position shown, line 25 is also the normaldirection and corresponds to line A0 of Fig. 1. Thus, by rotating member33 about the axis 24 the X-ray beam may be placed in positionscorresponding to lines B0 and C0 of Fig. 1.

Rotatably mounted on a member l4 forming part of a supporting device, isan arm l3 having a cylindrical portion 52. The pivot H is rotatablymounted in the portion i2 and secured thereto by means of nuts 34 and acollar 48. A screw serves to secure arm [3 in the proper position onmember i4.

The cylindrical portion 52 has a flange I6 which engages the flange I!of the supporting member 33. t is, as shown in Fig. 3, provided withthree notches 35, 36 and 31, notches 3'! and 35 being located 98 fromnotch 36. Pivoted on member 33 at a point it (see Fig. 2) is a lever 38having a latch portion 20 adapted to engage one of the notches 35, 36and 31, a handle portion i9 and an arm 2!. A tension spring 22 havingone end connected to arm 2! and its other end fixed to member 33 at apoint 39 serves to hold portion 20 in engagement with one of thenotches. The latch portion 20 can be lifted from the notches by exertingpressure on the handle portion l3 and then the supporting device 33 ispermitted to rotate about the axis 24.

In operating the apparatus, the arm 33 is rotated around axis 2 3 untilportion 20 engages notch 33 and the X-ray tube is in the centralposition. Member it is then moved until its axis 26and thus the axis 25of the X-ray beam-is perpendicular to the surface of plate 30 at thepoint 0.

The distance between the diaphragm 9 and the surface of the body 30under examination may be adjusted by means of a supporting device with avertically slidable carrier for example a supporting device as describedin United States patent specification 2,051,508 of Wildeboer. A deviceof this kind is shown in Fig. 4. It has a pedestal M and a carrier 45.The carrier can be displaced along the vertically arranged tubularportion 50 of the stand. The carrier ib has a horizontally slidable armil, provided with an end portion 62. The member it forms part of the endportion 42.

The distance between the diaphragm 0 and the surface of body 36 is suchthat the axis 24 passes through the point 0. This distance remains thesame in all cases and is for example about 50 mms.

Arm i3 is then rotated about the member l4 until the projection of thisarm upon the surface of body 30 intersects the right angle between thetwo stresses to be investigated, i. e., in Fig. 1 it lies in a planenormal to the surface of the body 30 and passing through line OK. Thearm i3 is then secured in this position by tightening screw 55.

The X-ray beam is shown in the normal or central position, i. e., in thedirection of line A0 in Fig. 1. After taking a radiograph with the beamin this position, member 33 is rotated around axis 25 into positionscorresponding to notches 35 and 37 where the second and thirdradiographs are taken.

I prefer to make the axis 25 coincide with the axis 25 of the X-ray beambecause in this case rotation of the arm l3 about axis 26 can beeffected without displacing the point at which the X-ray beam impingesupon the surface of the plate.

The angles need not be exactly the values given above, but may varyslightly, for instance may vary about i- 5%. However, the best resultsare obtained when the axis of rotation makes an nection with specificexamples, I do not wish to be limited thereto but desire the appendedclaims to be construed as broadly as permissible in view of the priorart.

What I claim is:

1. An apparatus for investigating stresses in material comprising meansfor producing a narrow X-ray beam including an X-ray tube and adiaphragm having an aperture, a supporting member and a second member,carrying said X-ray tube and diaphragm said members being rotatablyconnected to each other by means of a pivot, the axis of said pivotforming an angle of about 30 with the axis of said X-ray beam andintersecting the same on the side of the diaphragm remote from the X-raytube, and means associated with said members to indicate when said X-raybeam is in each of three predetermined positions, the planes throughsaid axis and the axis of the X-ray beam when in two of said positionsforming an angle lying between and 208 and the plane through said axisand the axis of said X-ray beam when in its third position forming equalangles with said first two planes.

2. An apparatus for investigating stresses in material comprising meansfor producing a narrow X-ray beam including an X-ray tube and adiaphragm having an aperture, a supporting member and a second memberrotatably connected to said supporting member by means of a pivot andcarrying said X-ray tube and diaphragm, the axis of said pivot formingan angle of about with the axis of said X-ray beam and intersecting thesame on the side of the diaphragm remote from. the X-ray tube, and meansto indicate the position of the X-ray beam comprising a disc associatedwith said first member and concentric with the axis of said pivot, saiddisc being provided with three notches spaced apart at equal angles ofabout 98, and a member associated with said second member and adapted toselectively engage the notches.

3. An apparatus for investigating stresses in material comprising meansfor producing a narrow X-ray beam including an X-ray tube and diaphragmhaving an aperture, a supporting arm, a member pivotally connected withsaid arm and a second member pivotally connected with said first member,the axis of pivoting between said first and second member lying in aplane with the axis of pivoting between said first member and said armand forming an angle of about 30 therewith and with the axis of saidX-ray beam and intersecting the latter on the side of the diaphragmremote from the X-ray tube, said second member carrying said X-ray tubeand diaphragm.

4. An apparatus for investigating stresses in material comprising meansfor producing an X- ray beam of small cross section including an Xraytube and a diaphragm provided with a small aperture, a supporting arm, amember pivotally connected with said arm, a second member pivotallyconnected with said first member and carrying said X-ray tube anddiaphragm, the axis of pivoting between said two members lying in aplane with the axis of pivoting of said first member and said arm andforming an angle of about 30 therewith and with the axis of the X-raybeam. and intersecting the beam on the side of the diaphragm remote fromthe X-ray tube, and means to support a photographic film transverse theaxis of the X-ray beam at a point between said diaphragm and the pointof intersection of said two axes of pivoing.

5. An X-ray apparatus comprising means for producing a narrow X-ray beamincluding an X-ray tube and a diaphragm provided with an aperture, asupporting arm and a member pivotally connected therewith and a secondmember pivotally connected with said first member, the axis of pivotingbetween said first and said second member lying in a plane with the axisof pivoting between said first member and said arm and forming an angleof about 30 with said latter axis and with the axis of said X-ray beamand intersecting the axis of said beam on the side of the diaphragmremote from said X-ray tube, said second member carrying said X-ray tubeand diaphragm, the axis of said X-ray beam coinciding with the axis ofpivoting between said first member and said arm when in the plane ofsaid axes of pivoting.

HENDRIK CORNELIS BERTRAM.

